Biology subjects

Miller, Y. I.

Publications and source records attributed to Miller, Y. I..

8 recordsLinked to original sources

bioRxiv2026

Therapeutic AIBP expression contributes to synaptic preservation and vision restoration against glaucomatous neuroinflammation

Lowering intraocular pressure (IOP) is the only approved treatment for glaucoma, yet retinal ganglion cell (RGC) degeneration and vision loss often progress despite reducing IOP. Apolipoprotein A-I binding protein (AIBP) stabilizes ATP-binding cassette subfamily A member 1 (ABCA1) and promotes cholesterol efflux, thus controlling cholesterol-rich lipid rafts and restraining lipid raft-dependent Toll-like receptor 4 (TLR4) inflammatory signaling. Here we show that AAV2-mediated expression of human AIBP (hAIBP) preserves inner retinal synaptic integrity and visual function in experimental glaucoma without altering IOP. In DBA/2J mice, a single intravitreal injection of AAV2-hAIBP at 5 months protected RGCs and preserved pattern electroretinogram and pattern visual evoked potential responses at 10 months, even though IOP was indistinguishable from empty-vector controls. AAV2-hAIBP preserved CaMKII and synapsin phosphorylation, restored synaptophysin and PSD95 in the inner plexiform layer, and reduced the expression of TLR4, complement C1q, IBA1, IL-1b, and IL-6 induction in Muller glia and microglia. Comparable protection was observed in microbead-induced ocular hypertension in C57BL/6 mice, both when the AAV2-hAIBP was delivered before microbead injection and when it was delivered after IOP elevation was established. Elevated IOP reduced endogenous retinal AIBP and ABCA1 expression, and AAV2-hAIBP restored both. Protection required the TLR4-binding domain, as an AIBP mutant lacking this domain failed to preserve RGCs. Conversely, AIBP knockout retinas exhibited increased CaMKII phosphorylation and reduced synaptophysin in the absence of elevated IOP. These findings identify synaptic preservation through the AIBP-TLR4 axis as an IOP-independent therapeutic mechanism and support AAV2-hAIBP as a candidate gene therapy for glaucoma.

neuroscience↗

bioRxiv2026

Excessive cholesterol accumulation in microglia increases neuronal synaptic vulnerability to amyloid-beta

Cholesterol efflux is an important determinant of cellular lipid homeostasis. However, how microglial excessive cholesterol accumulation affects neuronal synaptic integrity remains poorly understood, particularly in the context of Alzheimer's disease. Here, we utilized a conditional knockout mouse model targeting the cholesterol transporters ABCA1 and ABCG1 in microglia. The microglia-specific ABCA1/ABCG1 deficiency triggered marked cholesterol accumulation, microglial hypertrophy, downregulation of the homeostatic marker P2ry12, and upregulation of the reactivity-associated marker CD11b, indicating shift toward a reactive phenotype. This phenotype was accompanied by increased reactive oxygen species, consistent with enhanced oxidative stress in ABCA1/ABCG1-deficient microglia compared with control. Using organotypic hippocampal slice cultures, we investigated the downstream neuronal outcomes of microglial ABCA1/ABCG1 deficiency. Under basal conditions, microglial ABCA1/ABCG1 knockdown did not significantly alter dendritic spine density in CA1 pyramidal neurons. However, upon exposure to amyloid-beta (A{beta}) stress, microglial ABCA1/ABCG1 deficiency markedly exacerbated dendritic spine loss in CA1 pyramidal neurons. Taken together, our findings highlight an important role for ABCA1/ABCG1-dependent cholesterol efflux in maintaining microglial homeostasis and limiting neuronal synaptic vulnerability to A{beta}-associated stress. These results support further investigation of microglial cholesterol transport as a potential target for preserving synaptic resilience in Alzheimer's disease.

neuroscience↗

bioRxiv2026

Enhanced TRPV1 activation through TLR-4 and PKA signaling in Dorsal Root Ganglia Neurons

The excitability of afferents involved in nociceptive signaling reflects the interaction of several co-expressed membrane receptors. Current studies have shown that Toll-like receptor-4 (TLR-4) signaling can exacerbate excitation evoked by transient receptor potential vanilloid type 1 (TRPV1) activity, and this interaction plays a key role in driving and sustaining facilitated pain states. The mechanism by which this potentiated TRPV1 activity secondary to TLR-4 agonism occurs in sensory neurons remains unknown, although intracellular kinase activity is a strong candidate. To address this hypothesized linkage, neuronal cell cultures prepared from dorsal root ganglia (DRG) of male wildtype (WT) and Tlr4-/- mice were used to evaluate calcium transients of neurons after capsaicin administration in culture, pre-treated for 30 minutes with the TLR-4 agonist, lipopolysaccharide (LPS). TRPV1 protein expression at the neuron surface in cultured DRG cells with or without LPS treatment was quantified by flow cytometry assay. The roles of protein kinase A (PKA) and C were assessed using selective inhibitors (KT5720 for PKA and Chelerythrine chloride for PKC) applied to WT-DRG neurons or administered in vivo by intraplantar or intrathecal injection, prior to LPS and capsaicin administration. Behavioral effects of in vivo TRPV1 activation were assessed through paw flinch responses evoked by intraplantar capsaicin injection and by hind paw tactile thresholds measured by von Frey filaments. LPS incubation in cultured DRG neurons enhances the intensity of calcium influx following TRPV1 activation in WT but not Tlr4-/ cells. The augmented calcium influx evoked by capsaicin was prevented by the inhibition of PKA but not PKC. Similarly, mice treated with LPS in the hind paw displayed greater nociceptive responding after capsaicin and increased tactile allodynia. The facilitated component was prevented by the local pre-treatment with the PKA inhibitor. Correspondingly, lumbar spinal blockade of PKA resulted in temporary reversal of hyperalgesia induced by intrathecal LPS injection in mice. Together, these results demonstrate the relevance of TLR-4 in modulating the excitability of nociceptor signaling by regulating TRPV1, thereby influencing pain transmission through PKA signaling.

pharmacology and toxicology↗

bioRxiv2025

Progressive Loss of Astrocytic AIBP Expression during Alzheimer's Disease Pathology

Astrocytes and microglia play crucial roles in mediating neuroinflammation during Alzheimers disease (AD) progression. ApoA-I binding protein (APOA1BP, also known as AIBP/NAXE) attenuates neuroinflammation by blocking amyloid {beta}-induced TLR4 inflammaraft formation and oxidative stress. Apoa1bp knockout in APP/PS1 mice exacerbates microgliosis, increases amyloid plaque burden, neuronal cell loss, and reduces survival at 6 months. Although APOA1BP mRNA is ubiquitously expressed in humans, its cell-type-specific distribution in the brain remains unclear. To examine AIBP protein expression in the human brain, we performed immunohistochemistry on hippocampal sections from postmortem brain specimens from subjects aged 75-96 of both sexes. Using GFAP and IBA1 to label astrocytes and microglia, respectively, we found that AIBP protein was highly expressed in astrocytes, but not in microglia. Stratification of subjects by Braak stage (I-II, III-IV, V-VI) revealed a progressive decline in astrocytic AIBP expression with advancing AD pathology. Meta-analysis of RNA-seq profiling indicated enriched Apoa1bp expression in adult mouse astrocytes. Systemic Apoa1bp knockout in the APP/PS1 mouse exacerbated astrogliosis. These findings demonstrate that AIBP is predominantly expressed in astrocytes and its expression declines with AD progression, suggesting a potential role for AIBP in astrocyte-mediated neuroprotection and AD pathogenesis.

neuroscience↗

bioRxiv2025

Human dorsal root ganglia neuronal cell line to study nociceptive signaling: a new pipeline for pain therapy.

Nociceptive afferent neurons within the dorsal root ganglion (DRG) detect and relay painful stimuli from the periphery to the brain, and the malfunctioning of this process leads to sustained pain states. Animal model studies have been invaluable for demonstrating the importance of the DRG nociceptor in pain sensation and the development of related analgesic targets. However, there are functional biological differences between human and animal model nociceptors. Therefore, a complementary in vitro model of human nociception is critical to confirming the relevance of preclinical findings for therapeutic drug development. We characterized the nociceptive properties of differentiated cells from the human DRG-derived immortalized cell line HD10.6. Within differentiated HD10.6 cells, we documented the abundance and localization of nociceptive machinery central to regulating excitability and linked with pain sensation including ion channels TRPV1 and NaV1.7 and afferent peptides CGRP and Substance P. Using calcium influx imaging assays, we confirmed the electrical functionality of TRPV1 and NaV1.7 in HD10.6 cells, and through whole-cell patch clamp, we found similar baseline electrophysiological parameters of HD10.6 cells to those previously observed in human patient DRGs. Further, we found that differentiated HD10.6 cells express the mu opioid receptor 1 protein, and DAMGO, a mu agonist, blocks depolarization-evoked calcium influx in a naloxone-reversible fashion. Importantly, using an inflammatory cocktail, excitation and peripheral sensitization are induced within HD10.6 cells, mirroring nociceptors in a pain state during or after tissue damage or inflammation. Finally, HD10.6 cells were also cultured into dual-chambered microfluidic devices to mirror the biological anatomy of the nociceptor. Within this system, we demonstrated the uptake of adeno-associated-virus (AAV) by the peripheral terminals and AAV transport to the soma. Altogether, we have developed the use of HD10.6 cells to create a system of human nociceptive signaling on a chip to study human nociceptor physiology and intervention. PerspectiveThere are essential differences between human and animal model nociceptors. Here, we develop a physiological model of "nociceptive signaling on a chip" using human-derived nociceptors to ultimately enhance the translatability of preclinical afferent signaling research to the human patient.

neuroscience↗

bioRxiv2025

Increased atherosclerosis and expression of inflammarafts in macrophage foam cells in AIBP-deficient mice

Atherosclerotic lesions comprise different populations of macrophages, including lipid-laden macrophage foam cells and non-foamy, inflammatory macrophages, which play distinct roles in disease progression. Non-foamy macrophages express higher levels of inflammarafts - enlarged, cholesterol-rich lipid rafts hosting assemblies of inflammatory receptors - compared to foam cells in atherosclerotic lesions of Ldlr-/-mice. Apolipoprotein A-I binding protein (AIBP) has been shown to control lipid raft dynamics. This study investigated the effect of systemic AIBP deficiency on inflammaraft expression in foam cells and non-foamy macrophages in atherosclerotic lesions of hypercholesterolemic mice. A larger number of foam cells, with increased neutral lipid accumulation, populated atherosclerotic lesions in Apoa1bp-/-Ldlr-/-mice compared to Ldlr-/- mice. Importantly, AIBP-deficient foam cells expressed higher levels of TLR4 dimers and lipid rafts (markers of inflammarafts) than control mice, accompanied by larger atherosclerotic lesions and larger necrotic cores compared to Ldlr-/-mice. In a model of foam cells, Apoa1bp-/- bone marrow-derived macrophages incubated with oxidized LDL had increased expression of inflammation- and atherosclerosis-related genes. These results indicate that AIBP deficiency is associated with a proinflammatory transition of foam cells in which increased lipid accumulation is paradoxically associated with an increased expression of inflammarafts and correlates with the development of advanced atherosclerotic plaques.

immunology↗

bioRxiv2024

AIBP controls amyloid beta induced TLR4 inflammarafts and mitochondrial dysfunction in microglia

Microglia-driven neuroinflammation plays an important role in the development of Alzheimers disease (AD). Microglia activation is accompanied by the formation and chronic maintenance of TLR4 inflammarafts, defined as enlarged and cholesterol-rich lipid rafts serving as an assembly platform for TLR4 dimers and complexes of other inflammatory receptors. The secreted apoA-I binding protein (APOA1BP or AIBP) binds TLR4 and selectively targets cholesterol depletion machinery to TLR4 inflammaraft expressing inflammatory, but not homeostatic microglia. Here we demonstrated that amyloid-beta (A{beta}) induced formation of TLR4 inflammarafts in microglia in vitro and in the brain of APP/PS1 mice. Mitochondria in Apoa1bp-/- APP/PS1 microglia were hyperbranched and cupped, which was accompanied by increased ROS and the dilated ER. The size and number of A{beta} plaques and neuronal cell death were significantly increased, and the animal survival was decreased in Apoa1bp-/- APP/PS1 compared to APP/PS1 female mice. These results suggest that AIBP exerts control of TLR4 inflammarafts and mitochondrial dynamics in microglia and plays a protective role in AD associated oxidative stress and neurodegeneration.

neuroscience↗

bioRxiv2023

Restoring AIBP deficiency in the retina provides neuroprotection in glaucoma

Glaucoma is a neurodegenerative disease manifested in retinal ganglion cell (RGC) death and irreversible blindness. While lowering intraocular pressure (IOP) is the only proven therapeutic strategy in glaucoma, it is insufficient for preventing disease progression, thus justifying the recent focus on targeting retinal neuroinflammation and preserving RGCs. We have identified apolipoprotein A-I binding protein (AIBP) as the protein regulating several mechanisms of retinal neurodegeneration. AIBP controls excessive cholesterol accumulation via upregulating the cholesterol transporter ATP-binding cassette transporter 1 (ABCA1) and reduces inflammatory signaling via toll-like receptor 4 (TLR4) and mitochondrial dysfunction. ABCA1, TLR4 and oxidative phosphorylation components are genetically linked to primary open-angle glaucoma. Here we demonstrated that AIBP and ABCA1 expression was decreased, while TLR4, interleukin 1 {beta} (IL-1{beta}), and the cholesterol content increased in the retina of patients with glaucoma and in mouse models of glaucoma. Restoring AIBP expression by a single intravitreal injection of adeno-associated virus (AAV)-AIBP protected RGCs in glaucomatous DBA/2J mice, in mice with microbead-induced chronic IOP elevation, and optic nerve crush. In addition, AIBP expression attenuated TLR4 and IL-1{beta} expression, localization of TLR4 to lipid rafts, reduced cholesterol accumulation, and ameliorated visual dysfunction. These studies collectively indicate that restoring AIBP expression in the glaucomatous retina reduces neuroinflammation and protects RGCs and Muller glia, suggesting the therapeutic potential of AAV-AIBP in human glaucoma. Significance StatementLowering intraocular pressure is insufficient to prevent progressive neuroinflammation, retinal ganglion cell (RGC) death and vision loss in glaucoma. We show that reduced expression of AIBP is associated with increased markers of neuroinflammation, TLR4 and IL-1{beta}, in human glaucomatous retina and mouse models of glaucoma. Restoring AIBP expression by an intravitreal injection of AAV-AIBP protects RGCs and preserves visual function in mouse models of glaucoma. Mechanistically, we demonstrate that AAV-AIBP disrupts TLR4-lipid raft formation and attenuates phosphorylation of AMPK, ERK1/2 and p38 and expression of TLR4 and IL-1{beta} in vivo. Collectively, our findings suggest that AIBP-mediated disruption of retinal TLR4-lipid rafts can prevent RGC loss and demonstrate the therapeutic potential of AAV-AIBP in treatment of human glaucoma.

neuroscience↗